Additive manufacturing is a rapidly growing field with a wide range of applications. Presently, there exists a need for the measurement of powder absorptivity for use in the analysis and modeling of laser-material interactions in the additive manufacturing build process. The absorptivity of powder depends not only on material type and laser wavelength; it is sensitive to the size distribution of the particles, particle shape, powder thickness and porosity.
Existing systems, such as for example the system described in Absorptance of powder materials suitable for laser sintering by N. Tolochko et al, (Rapid Prototyping Journal 6.155. 2000), measure the reflected light from the powder with the help of an integrating sphere and are typically complex. The distribution of the scattered light is unknown and even the small absorption in the integrating sphere coating can affect the result.
There is therefore a need for a simple compact system and method for performing fast, accurate measurements of laser absorptivity of powders.